Abstract: For the ethylene oxide purification column system in an EO/EG plant, Aspen HYSYS was used to dynamically simulate the overpressure scenarios such as the failure of cooling water, power and control valve, so as to obtain the peak relief capacity of safety valve and the changes in operating parameters including tower pressure, temperature, medium composition and reboiler heat duty under different overpressure scenarios. Taking the cooling water failure scenario as an example, the peak discharge flowrate of safety valve from the dynamic simulation is 215 t/h, significantly lower than 313 t/h from the traditional estimation method. Dynamic simulation can provide basis for the design optimization of safety valve selection, safety valve discharge diffusion calculation and discharge gas treatment scheme.

Key words: EO purification column, dynamic simulation, overpressure scenario, peak relief capacity of safety valve